/*
 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package org.eclipse.imagen.media.opimage;

import java.awt.Rectangle;
import java.awt.image.DataBuffer;
import java.awt.image.Raster;
import java.awt.image.RenderedImage;
import java.awt.image.WritableRaster;
import java.util.Map;
// import org.eclipse.imagen.media.test.OpImageTester;
import org.eclipse.imagen.AreaOpImage;
import org.eclipse.imagen.BorderExtender;
import org.eclipse.imagen.ImageLayout;
import org.eclipse.imagen.KernelJAI;
import org.eclipse.imagen.RasterAccessor;
import org.eclipse.imagen.RasterFormatTag;

/**
 * An OpImage class to perform convolution on a source image.
 *
 * <p>This class implements a convolution operation. Convolution is a spatial operation that computes each output sample
 * by multiplying elements of a kernel with the samples surrounding a particular source sample.
 *
 * <p>For each destination sample, the kernel is rotated 180 degrees and its "key element" is placed over the source
 * pixel corresponding with the destination pixel. The kernel elements are multiplied with the source pixels under them,
 * and the resulting products are summed together to produce the destination sample value.
 *
 * <p>Example code for the convolution operation on a single sample dst[x][y] is as follows. First your original kernel
 * is rotated by 180 degrees, then the following - assuming the kernel is of size M rows x N columns and the rotated
 * kernel's key element is at position (xKey, yKey):
 *
 * <pre>
 * dst[x][y] = 0;
 * for (int i = -xKey; i < M - xKey; i++) {
 *     for (int j = -yKey; j < N - yKey; j++) {
 *         dst[x][y] += src[x + i][y + j] * kernel[xKey + i][yKey + j];
 *     }
 * }
 * </pre>
 *
 * <p>Convolution, or any neighborhood operation, leaves a band of pixels around the edges undefined, i.e., for a 3x3
 * kernel, only four kernel elements and four source pixels contribute to the destination pixel located at (0,0). Such
 * pixels are not includined in the destination image. A BorderOpImage may be used to add an appropriate border to the
 * source image in order to avoid shrinkage of the image boundaries.
 *
 * <p>The Kernel cannot be bigger in any dimension than the image data.
 *
 * @see KernelJAI
 */
final class ConvolveOpImage extends AreaOpImage {

    /** The kernel with which to do the convolve operation. */
    protected KernelJAI kernel;

    /** Kernel variables. */
    private int kw, kh, kx, ky;

    /**
     * Creates a ConvolveOpImage given a ParameterBlock containing the image source and pre-rotated convolution kernel.
     * The image dimensions are derived from the source image. The tile grid layout, SampleModel, and ColorModel may
     * optionally be specified by an ImageLayout object.
     *
     * @param source a RenderedImage.
     * @param extender a BorderExtender, or null.
     * @param layout an ImageLayout optionally containing the tile grid layout, SampleModel, and ColorModel, or null.
     * @param kernel the pre-rotated convolution KernelJAI.
     */
    public ConvolveOpImage(
            RenderedImage source, BorderExtender extender, Map config, ImageLayout layout, KernelJAI kernel) {
        super(
                source,
                layout,
                config,
                true,
                extender,
                kernel.getLeftPadding(),
                kernel.getRightPadding(),
                kernel.getTopPadding(),
                kernel.getBottomPadding());

        this.kernel = kernel;
        kw = kernel.getWidth();
        kh = kernel.getHeight();
        kx = kernel.getXOrigin();
        ky = kernel.getYOrigin();
    }

    /**
     * Performs convolution on a specified rectangle. The sources are cobbled.
     *
     * @param sources an array of source Rasters, guaranteed to provide all necessary source data for computing the
     *     output.
     * @param dest a WritableRaster tile containing the area to be computed.
     * @param destRect the rectangle within dest to be processed.
     */
    protected void computeRect(Raster[] sources, WritableRaster dest, Rectangle destRect) {
        // Retrieve format tags.
        RasterFormatTag[] formatTags = getFormatTags();

        Raster source = sources[0];
        Rectangle srcRect = mapDestRect(destRect, 0);

        RasterAccessor srcAccessor = new RasterAccessor(
                source, srcRect, formatTags[0], getSourceImage(0).getColorModel());
        RasterAccessor dstAccessor = new RasterAccessor(dest, destRect, formatTags[1], getColorModel());

        switch (dstAccessor.getDataType()) {
            case DataBuffer.TYPE_BYTE:
                byteLoop(srcAccessor, dstAccessor);
                break;
            case DataBuffer.TYPE_INT:
                intLoop(srcAccessor, dstAccessor);
                break;
            case DataBuffer.TYPE_SHORT:
                shortLoop(srcAccessor, dstAccessor);
                break;
            case DataBuffer.TYPE_USHORT:
                ushortLoop(srcAccessor, dstAccessor);
                break;
            case DataBuffer.TYPE_FLOAT:
                floatLoop(srcAccessor, dstAccessor);
                break;
            case DataBuffer.TYPE_DOUBLE:
                doubleLoop(srcAccessor, dstAccessor);
                break;

            default:
        }

        // If the RasterAccessor object set up a temporary buffer for the
        // op to write to, tell the RasterAccessor to write that data
        // to the raster no that we're done with it.
        if (dstAccessor.isDataCopy()) {
            dstAccessor.clampDataArrays();
            dstAccessor.copyDataToRaster();
        }
    }

    private void byteLoop(RasterAccessor src, RasterAccessor dst) {
        int dwidth = dst.getWidth();
        int dheight = dst.getHeight();
        int dnumBands = dst.getNumBands();

        float[] kdata = kernel.getKernelData();
        int kw = kernel.getWidth();
        int kh = kernel.getHeight();

        byte dstDataArrays[][] = dst.getByteDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        byte srcDataArrays[][] = src.getByteDataArrays();
        int srcBandOffsets[] = src.getBandOffsets();
        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();

        for (int k = 0; k < dnumBands; k++) {
            byte dstData[] = dstDataArrays[k];
            byte srcData[] = srcDataArrays[k];
            int srcScanlineOffset = srcBandOffsets[k];
            int dstScanlineOffset = dstBandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int srcPixelOffset = srcScanlineOffset;
                int dstPixelOffset = dstScanlineOffset;

                for (int i = 0; i < dwidth; i++) {
                    float f = 0.5F;
                    int kernelVerticalOffset = 0;
                    int imageVerticalOffset = srcPixelOffset;
                    for (int u = 0; u < kh; u++) {
                        int imageOffset = imageVerticalOffset;
                        for (int v = 0; v < kw; v++) {
                            f += ((int) srcData[imageOffset] & 0xff) * kdata[kernelVerticalOffset + v];
                            imageOffset += srcPixelStride;
                        }
                        kernelVerticalOffset += kw;
                        imageVerticalOffset += srcScanlineStride;
                    }

                    int val = (int) f;
                    if (val < 0) {
                        val = 0;
                    } else if (val > 255) {
                        val = 255;
                    }
                    dstData[dstPixelOffset] = (byte) val;
                    srcPixelOffset += srcPixelStride;
                    dstPixelOffset += dstPixelStride;
                }
                srcScanlineOffset += srcScanlineStride;
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    private void shortLoop(RasterAccessor src, RasterAccessor dst) {
        int dwidth = dst.getWidth();
        int dheight = dst.getHeight();
        int dnumBands = dst.getNumBands();

        float[] kdata = kernel.getKernelData();
        int kw = kernel.getWidth();
        int kh = kernel.getHeight();

        short dstDataArrays[][] = dst.getShortDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        short srcDataArrays[][] = src.getShortDataArrays();
        int srcBandOffsets[] = src.getBandOffsets();
        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();

        for (int k = 0; k < dnumBands; k++) {
            short dstData[] = dstDataArrays[k];
            short srcData[] = srcDataArrays[k];
            int srcScanlineOffset = srcBandOffsets[k];
            int dstScanlineOffset = dstBandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int srcPixelOffset = srcScanlineOffset;
                int dstPixelOffset = dstScanlineOffset;

                for (int i = 0; i < dwidth; i++) {
                    float f = 0.5F;
                    int kernelVerticalOffset = 0;
                    int imageVerticalOffset = srcPixelOffset;
                    for (int u = 0; u < kh; u++) {
                        int imageOffset = imageVerticalOffset;
                        for (int v = 0; v < kw; v++) {
                            f += (srcData[imageOffset]) * kdata[kernelVerticalOffset + v];
                            imageOffset += srcPixelStride;
                        }
                        kernelVerticalOffset += kw;
                        imageVerticalOffset += srcScanlineStride;
                    }

                    int val = (int) f;
                    if (val < Short.MIN_VALUE) {
                        val = Short.MIN_VALUE;
                    } else if (val > Short.MAX_VALUE) {
                        val = Short.MAX_VALUE;
                    }

                    dstData[dstPixelOffset] = (short) val;
                    srcPixelOffset += srcPixelStride;
                    dstPixelOffset += dstPixelStride;
                }
                srcScanlineOffset += srcScanlineStride;
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    private void ushortLoop(RasterAccessor src, RasterAccessor dst) {
        int dwidth = dst.getWidth();
        int dheight = dst.getHeight();
        int dnumBands = dst.getNumBands();

        float[] kdata = kernel.getKernelData();
        int kw = kernel.getWidth();
        int kh = kernel.getHeight();

        short dstDataArrays[][] = dst.getShortDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        short srcDataArrays[][] = src.getShortDataArrays();
        int srcBandOffsets[] = src.getBandOffsets();
        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();

        for (int k = 0; k < dnumBands; k++) {
            short dstData[] = dstDataArrays[k];
            short srcData[] = srcDataArrays[k];
            int srcScanlineOffset = srcBandOffsets[k];
            int dstScanlineOffset = dstBandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int srcPixelOffset = srcScanlineOffset;
                int dstPixelOffset = dstScanlineOffset;

                for (int i = 0; i < dwidth; i++) {
                    float f = 0.5F;
                    int kernelVerticalOffset = 0;
                    int imageVerticalOffset = srcPixelOffset;
                    for (int u = 0; u < kh; u++) {
                        int imageOffset = imageVerticalOffset;
                        for (int v = 0; v < kw; v++) {
                            f += (srcData[imageOffset] & 0xffff) * kdata[kernelVerticalOffset + v];
                            imageOffset += srcPixelStride;
                        }
                        kernelVerticalOffset += kw;
                        imageVerticalOffset += srcScanlineStride;
                    }
                    int val = (int) f;
                    if (val < 0) {
                        val = 0;
                    } else if (val > 0xffff) {
                        val = 0xffff;
                    }

                    dstData[dstPixelOffset] = (short) val;
                    srcPixelOffset += srcPixelStride;
                    dstPixelOffset += dstPixelStride;
                }
                srcScanlineOffset += srcScanlineStride;
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    private void intLoop(RasterAccessor src, RasterAccessor dst) {
        int dwidth = dst.getWidth();
        int dheight = dst.getHeight();
        int dnumBands = dst.getNumBands();

        float[] kdata = kernel.getKernelData();
        int kw = kernel.getWidth();
        int kh = kernel.getHeight();

        int dstDataArrays[][] = dst.getIntDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        int srcDataArrays[][] = src.getIntDataArrays();
        int srcBandOffsets[] = src.getBandOffsets();
        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();

        for (int k = 0; k < dnumBands; k++) {
            int dstData[] = dstDataArrays[k];
            int srcData[] = srcDataArrays[k];
            int srcScanlineOffset = srcBandOffsets[k];
            int dstScanlineOffset = dstBandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int srcPixelOffset = srcScanlineOffset;
                int dstPixelOffset = dstScanlineOffset;

                for (int i = 0; i < dwidth; i++) {
                    float f = 0.5F;
                    int kernelVerticalOffset = 0;
                    int imageVerticalOffset = srcPixelOffset;
                    for (int u = 0; u < kh; u++) {
                        int imageOffset = imageVerticalOffset;
                        for (int v = 0; v < kw; v++) {
                            f += ((int) srcData[imageOffset]) * kdata[kernelVerticalOffset + v];
                            imageOffset += srcPixelStride;
                        }
                        kernelVerticalOffset += kw;
                        imageVerticalOffset += srcScanlineStride;
                    }

                    dstData[dstPixelOffset] = (int) f;
                    srcPixelOffset += srcPixelStride;
                    dstPixelOffset += dstPixelStride;
                }
                srcScanlineOffset += srcScanlineStride;
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    private void floatLoop(RasterAccessor src, RasterAccessor dst) {
        int dwidth = dst.getWidth();
        int dheight = dst.getHeight();
        int dnumBands = dst.getNumBands();

        float[] kdata = kernel.getKernelData();
        int kw = kernel.getWidth();
        int kh = kernel.getHeight();

        float dstDataArrays[][] = dst.getFloatDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        float srcDataArrays[][] = src.getFloatDataArrays();
        int srcBandOffsets[] = src.getBandOffsets();
        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();

        for (int k = 0; k < dnumBands; k++) {
            float dstData[] = dstDataArrays[k];
            float srcData[] = srcDataArrays[k];
            int srcScanlineOffset = srcBandOffsets[k];
            int dstScanlineOffset = dstBandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int srcPixelOffset = srcScanlineOffset;
                int dstPixelOffset = dstScanlineOffset;

                for (int i = 0; i < dwidth; i++) {
                    float f = 0.0F;
                    int kernelVerticalOffset = 0;
                    int imageVerticalOffset = srcPixelOffset;
                    for (int u = 0; u < kh; u++) {
                        int imageOffset = imageVerticalOffset;
                        for (int v = 0; v < kw; v++) {
                            f += (srcData[imageOffset]) * kdata[kernelVerticalOffset + v];
                            imageOffset += srcPixelStride;
                        }
                        kernelVerticalOffset += kw;
                        imageVerticalOffset += srcScanlineStride;
                    }

                    dstData[dstPixelOffset] = f;
                    srcPixelOffset += srcPixelStride;
                    dstPixelOffset += dstPixelStride;
                }
                srcScanlineOffset += srcScanlineStride;
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    private void doubleLoop(RasterAccessor src, RasterAccessor dst) {
        int dwidth = dst.getWidth();
        int dheight = dst.getHeight();
        int dnumBands = dst.getNumBands();

        float[] kdata = kernel.getKernelData();
        int kw = kernel.getWidth();
        int kh = kernel.getHeight();

        double dstDataArrays[][] = dst.getDoubleDataArrays();
        int dstBandOffsets[] = dst.getBandOffsets();
        int dstPixelStride = dst.getPixelStride();
        int dstScanlineStride = dst.getScanlineStride();

        double srcDataArrays[][] = src.getDoubleDataArrays();
        int srcBandOffsets[] = src.getBandOffsets();
        int srcPixelStride = src.getPixelStride();
        int srcScanlineStride = src.getScanlineStride();

        for (int k = 0; k < dnumBands; k++) {
            double dstData[] = dstDataArrays[k];
            double srcData[] = srcDataArrays[k];
            int srcScanlineOffset = srcBandOffsets[k];
            int dstScanlineOffset = dstBandOffsets[k];
            for (int j = 0; j < dheight; j++) {
                int srcPixelOffset = srcScanlineOffset;
                int dstPixelOffset = dstScanlineOffset;

                for (int i = 0; i < dwidth; i++) {
                    double f = 0.5;
                    int kernelVerticalOffset = 0;
                    int imageVerticalOffset = srcPixelOffset;
                    for (int u = 0; u < kh; u++) {
                        int imageOffset = imageVerticalOffset;
                        for (int v = 0; v < kw; v++) {
                            f += (srcData[imageOffset]) * kdata[kernelVerticalOffset + v];
                            imageOffset += srcPixelStride;
                        }
                        kernelVerticalOffset += kw;
                        imageVerticalOffset += srcScanlineStride;
                    }

                    dstData[dstPixelOffset] = f;
                    srcPixelOffset += srcPixelStride;
                    dstPixelOffset += dstPixelStride;
                }
                srcScanlineOffset += srcScanlineStride;
                dstScanlineOffset += dstScanlineStride;
            }
        }
    }

    //     public static OpImage createTestImage(OpImageTester oit) {
    //         float data[] = {0.05f,0.10f,0.05f,
    //                         0.10f,0.40f,0.10f,
    //                         0.05f,0.10f,0.05f};
    //         KernelJAI kJAI = new KernelJAI(3,3,1,1,data);
    //         return new ConvolveOpImage(oit.getSource(), null, null,
    //                                    new ImageLayout(oit.getSource()),
    //                                    kJAI);
    //     }

    //     public static void main(String args[]) {
    //         String classname = "org.eclipse.imagen.media.opimage.ConvolveOpImage";
    //         OpImageTester.performDiagnostics(classname,args);
    //     }
}
